diff options
Diffstat (limited to 'kernel/arch/arm/mach-tegra/cpuidle-tegra20.c')
| -rw-r--r-- | kernel/arch/arm/mach-tegra/cpuidle-tegra20.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-tegra/cpuidle-tegra20.c b/kernel/arch/arm/mach-tegra/cpuidle-tegra20.c new file mode 100644 index 000000000..7469347b1 --- /dev/null +++ b/kernel/arch/arm/mach-tegra/cpuidle-tegra20.c @@ -0,0 +1,226 @@ +/* + * CPU idle driver for Tegra CPUs + * + * Copyright (c) 2010-2012, NVIDIA Corporation. + * Copyright (c) 2011 Google, Inc. + * Author: Colin Cross <ccross@android.com> + * Gary King <gking@nvidia.com> + * + * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include <linux/clk/tegra.h> +#include <linux/tick.h> +#include <linux/cpuidle.h> +#include <linux/cpu_pm.h> +#include <linux/kernel.h> +#include <linux/module.h> + +#include <asm/cpuidle.h> +#include <asm/smp_plat.h> +#include <asm/suspend.h> + +#include "flowctrl.h" +#include "iomap.h" +#include "irq.h" +#include "pm.h" +#include "reset.h" +#include "sleep.h" + +#ifdef CONFIG_PM_SLEEP +static bool abort_flag; +static atomic_t abort_barrier; +static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index); +#define TEGRA20_MAX_STATES 2 +#else +#define TEGRA20_MAX_STATES 1 +#endif + +static struct cpuidle_driver tegra_idle_driver = { + .name = "tegra_idle", + .owner = THIS_MODULE, + .states = { + ARM_CPUIDLE_WFI_STATE_PWR(600), +#ifdef CONFIG_PM_SLEEP + { + .enter = tegra20_idle_lp2_coupled, + .exit_latency = 5000, + .target_residency = 10000, + .power_usage = 0, + .flags = CPUIDLE_FLAG_COUPLED, + .name = "powered-down", + .desc = "CPU power gated", + }, +#endif + }, + .state_count = TEGRA20_MAX_STATES, + .safe_state_index = 0, +}; + +#ifdef CONFIG_PM_SLEEP +#ifdef CONFIG_SMP +static int tegra20_reset_sleeping_cpu_1(void) +{ + int ret = 0; + + tegra_pen_lock(); + + if (readb(tegra20_cpu1_resettable_status) == CPU_RESETTABLE) + tegra20_cpu_shutdown(1); + else + ret = -EINVAL; + + tegra_pen_unlock(); + + return ret; +} + +static void tegra20_wake_cpu1_from_reset(void) +{ + tegra_pen_lock(); + + tegra20_cpu_clear_resettable(); + + /* enable cpu clock on cpu */ + tegra_enable_cpu_clock(1); + + /* take the CPU out of reset */ + tegra_cpu_out_of_reset(1); + + /* unhalt the cpu */ + flowctrl_write_cpu_halt(1, 0); + + tegra_pen_unlock(); +} + +static int tegra20_reset_cpu_1(void) +{ + if (!cpu_online(1) || !tegra20_reset_sleeping_cpu_1()) + return 0; + + tegra20_wake_cpu1_from_reset(); + return -EBUSY; +} +#else +static inline void tegra20_wake_cpu1_from_reset(void) +{ +} + +static inline int tegra20_reset_cpu_1(void) +{ + return 0; +} +#endif + +static bool tegra20_cpu_cluster_power_down(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + while (tegra20_cpu_is_resettable_soon()) + cpu_relax(); + + if (tegra20_reset_cpu_1() || !tegra_cpu_rail_off_ready()) + return false; + + tick_broadcast_enter(); + + tegra_idle_lp2_last(); + + tick_broadcast_exit(); + + if (cpu_online(1)) + tegra20_wake_cpu1_from_reset(); + + return true; +} + +#ifdef CONFIG_SMP +static bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + tick_broadcast_enter(); + + cpu_suspend(0, tegra20_sleep_cpu_secondary_finish); + + tegra20_cpu_clear_resettable(); + + tick_broadcast_exit(); + + return true; +} +#else +static inline bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + return true; +} +#endif + +static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + bool entered_lp2 = false; + + if (tegra_pending_sgi()) + ACCESS_ONCE(abort_flag) = true; + + cpuidle_coupled_parallel_barrier(dev, &abort_barrier); + + if (abort_flag) { + cpuidle_coupled_parallel_barrier(dev, &abort_barrier); + abort_flag = false; /* clean flag for next coming */ + return -EINTR; + } + + local_fiq_disable(); + + tegra_set_cpu_in_lp2(); + cpu_pm_enter(); + + if (dev->cpu == 0) + entered_lp2 = tegra20_cpu_cluster_power_down(dev, drv, index); + else + entered_lp2 = tegra20_idle_enter_lp2_cpu_1(dev, drv, index); + + cpu_pm_exit(); + tegra_clear_cpu_in_lp2(); + + local_fiq_enable(); + + smp_rmb(); + + return entered_lp2 ? index : 0; +} +#endif + +/* + * Tegra20 HW appears to have a bug such that PCIe device interrupts, whether + * they are legacy IRQs or MSI, are lost when LP2 is enabled. To work around + * this, simply disable LP2 if the PCI driver and DT node are both enabled. + */ +void tegra20_cpuidle_pcie_irqs_in_use(void) +{ + pr_info_once( + "Disabling cpuidle LP2 state, since PCIe IRQs are in use\n"); + tegra_idle_driver.states[1].disabled = true; +} + +int __init tegra20_cpuidle_init(void) +{ + return cpuidle_register(&tegra_idle_driver, cpu_possible_mask); +} |